An aging water treatment plant, a nasty algae in Lake Erie and weeks of dry, still weather conspired to sabotage Toledo’s drinking water, experts say.

Mayor D. Michael Collins lifted the ban on drinking tap water Monday, saying tests showed the water is once again clear of the toxins that had sent more than 400,000 northwestern Ohioans scrambling for drinkable water since Saturday morning.

“Our water is safe,” Collins said. “Families can return to normal life.”

Collins said carbon and other chemicals were used to clean the water of toxic microcystin. Lucas County, with a population of 440,000 including Toledo, advised residents to flush hot water faucets for 15 minutes and cold for five minutes before drinking the water.

The water ban had been complicated because boiling the water, a common tool to combat contamination, only serves to make microcystin more concentrated, officials said. Stores sold out of bottled water quickly. Toledo opened a half-dozen bring-you-own-container water distribution sites. Fire stations helped out.

Problem last year

The all-clear was issued publicly at 9:29 a.m. ET. Six hours earlier, Collins announced that federal and state tests had indicated the water was fine, but city tests in two neighborhoods showed lingering, questionable levels of the toxin. Collins said he waited for more test results because he did not want to isolate those neighborhoods and because he wanted to wait until he could “put my head on a pillow and be comfortable with my decision.”

Toledo’s water woes were not the first involving algae in Lake Erie. Last year, about 2,000 residents of nearby Carroll Township were prohibited from drinking water from their taps for a few days because of toxins linked to the blue-green algae.

Water treatment plants aren’t required to test for microcystin under federal and state regulations. But Patrick Lawrence, a geography professor at the University of Toledo, credits Toledo with starting to test for the toxin last year amid concerns about the increasing algae growth in Lake Erie, which supplies the city water plant.

Lawrence said algae bloom has been a growing problem in the Great Lakes for years. That made Toledo ground-zero for the problem.

“Warm, shallow water is perfect for the algae,” Lawrence said. “Lake Erie is the shallowest lake and the western basin (near Toledo) is the shallowest part of the lake.”

The algae grows underwater, floats to the surface and releases toxins as it decays. Weeks of little wind or rain exacerbated the situation, he said.

Long-term challenge

Adding charcoal to the treatment process is a short-term fix, he added. The city’s 70-year-old plant needs upgrading, which could cost hundreds of millions of dollars. And there are the issues of wastewater treatment discharges, agriculture runoff and even yard fertilizers.

“I’m waiting for two or three days,” said Aretha Howard, of Toledo, to the Associated Press. “I have a pregnant daughter at home. She can’t drink this water.”

STATE REVIEW

Ohio Gov. John Kasich said the state will conduct a full review of what happened, including taking a look at Toledo’s aging water system and figuring out how to reduce pollution that feeds algae in the western end of Lake Erie.